SqlDataSourceCommandEventHandler Delegado

  • Referencia

Definición

Espacio de nombres:
System.Web.UI.WebControls
Ensamblado:
System.Web.dll

Representa el método que va a controlar los eventos Updating, Inserting y Deleting del control SqlDataSource.

public delegate void SqlDataSourceCommandEventHandler(System::Object ^ sender, SqlDataSourceCommandEventArgs ^ e);
public delegate void SqlDataSourceCommandEventHandler(object sender, SqlDataSourceCommandEventArgs e);
type SqlDataSourceCommandEventHandler = delegate of obj * SqlDataSourceCommandEventArgs -> unit
Public Delegate Sub SqlDataSourceCommandEventHandler(sender As Object, e As SqlDataSourceCommandEventArgs)

Parámetros

sender
Object

Origen del evento, el control SqlDataSource.

e
SqlDataSourceCommandEventArgs

Objeto SqlDataSourceCommandEventArgs que contiene los datos del evento.

Ejemplos

En el ejemplo de código siguiente se muestra cómo controlar el Inserting evento para realizar los pasos de preprocesamiento, como agregar un parámetro al DbCommand objeto contenido por para SqlDataSourceCommandEventArgs capturar el valor de un parámetro de salida, antes de realizar una acción de base de datos. En este ejemplo, un control realiza una DetailsView inserción en un escenario clásico de master-detail mediante un procedimiento almacenado. El valor del parámetro de salida, que representa la clave principal de la fila recién insertada, se examina cuando se genera el Inserted evento una vez completada la operación.

<%@Page  Language="C#" %>
<%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.Common" %>
<%@Import Namespace="System.Data.SqlClient" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
 private void On_Inserting(Object sender, SqlDataSourceCommandEventArgs e) {

    SqlParameter insertedKey = new SqlParameter("@PK_New", SqlDbType.Int);
    insertedKey.Direction    = ParameterDirection.Output;        
    e.Command.Parameters.Add(insertedKey);
 }

 private void On_Inserted(Object sender, SqlDataSourceStatusEventArgs e) {
    DbCommand command = e.Command;    
    
    // The label displays the primary key of the recently inserted row.
    Label1.Text = command.Parameters["@PK_New"].Value.ToString();
    
    // Force a refresh after the data is inserted.
    GridView1.DataBind();
 }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <asp:GridView
        id="GridView1"
        runat="server"
        AutoGenerateColumns="False"
        DataKeyNames="EmployeeID"        
        DataSourceID="SqlDataSource1">
        <columns>          
          <asp:BoundField HeaderText="First Name" DataField="FirstName" />
          <asp:BoundField HeaderText="Last Name" DataField="LastName" />
          <asp:BoundField HeaderText="Title" DataField="Title" />
          <asp:ButtonField ButtonType="Link" CommandName="Select" Text="Details..." />
        </columns>
      </asp:GridView>

      <asp:SqlDataSource
        id="SqlDataSource1"
        runat="server"
        ConnectionString="<%$ ConnectionStrings:MyNorthwind %>"
        SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees">
      </asp:SqlDataSource>

      <hr />

      <asp:DetailsView
        id="DetailsView1"
        runat="server"
        DataSourceID="SqlDataSource2"
        AutoGenerateRows="False"
        AutoGenerateInsertButton="True">
        <fields>
          <asp:BoundField HeaderText="First Name" DataField="FirstName" ReadOnly="False"/>
          <asp:BoundField HeaderText="Last Name" DataField="LastName" ReadOnly="False"/>
          <asp:TemplateField HeaderText="Title">
            <ItemTemplate>
              <asp:DropDownList
                id="TitleDropDownList"
                runat="server"
                selectedvalue="<%# Bind('Title') %>" >
                <asp:ListItem Selected="True">Sales Representative</asp:ListItem>
                <asp:ListItem>Sales Manager</asp:ListItem>
                <asp:ListItem>Vice President, Sales</asp:ListItem>
              </asp:DropDownList>
            </ItemTemplate>
          </asp:TemplateField>
          <asp:BoundField HeaderText="Notes" DataField="Notes" ReadOnly="False"/>
        </fields>
      </asp:DetailsView>


      <asp:SqlDataSource
        id="SqlDataSource2"
        runat="server"
        ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
        SelectCommand="SELECT * FROM Employees"
        InsertCommandType = "StoredProcedure"
        InsertCommand="sp_insertemployee"        
        OnInserting="On_Inserting"
        OnInserted ="On_Inserted"
        FilterExpression="EmployeeID={0}">
        <FilterParameters>
          <asp:ControlParameter Name="EmployeeID" ControlId="GridView1" PropertyName="SelectedValue" />
        </FilterParameters>
      </asp:SqlDataSource>

<!-- 
     -- An example sp_insertemployee stored procedure that returns
     -- the primary key of the row that was inserted in an OUT parameter.
     CREATE PROCEDURE sp_insertemployee 
        @FirstName nvarchar(10), 
        @LastName nvarchar(20) , 
        @Title nvarchar(30), 
        @Notes nvarchar(200), 
        @PK_New int OUTPUT
      AS
        INSERT INTO Employees(FirstName,LastName,Title,Notes)VALUES (@FirstName,@LastName,@Title,@Notes)
        SELECT @PK_New = @@IDENTITY
        RETURN (1)    
      GO
-->      

      <asp:Label 
        id="Label1"
        runat="server" />
      
    </form>
  </body>
</html>

<%@Page  Language="VB" %>
<%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.Common" %>
<%@Import Namespace="System.Data.SqlClient" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

 Sub On_Inserting(ByVal sender As Object, ByVal e As SqlDataSourceCommandEventArgs)

    Dim insertedKey As SqlParameter  
    insertedKey = New SqlParameter("@PK_New", SqlDbType.Int)
    insertedKey.Direction    = ParameterDirection.Output     
    
    e.Command.Parameters.Add(insertedKey)

 End Sub 'On_Inserting

 Sub On_Inserted(ByVal sender As Object, ByVal e As SqlDataSourceStatusEventArgs)
    Dim command As DbCommand 
    command = e.Command
    
    ' The label displays the primary key of the recently inserted row.
    Label1.Text = command.Parameters("@PK_New").Value.ToString()    
    
    ' Explicitly call DataBind to refresh the data
    ' and show the newly inserted row.
    GridView1.DataBind()
 End Sub 'On_Inserted

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <asp:GridView
        id="GridView1"
        runat="server"
        AutoGenerateColumns="False"
        DataKeyNames="EmployeeID"        
        DataSourceID="SqlDataSource1">
        <columns>          
          <asp:BoundField HeaderText="First Name" DataField="FirstName" />
          <asp:BoundField HeaderText="Last Name" DataField="LastName" />
          <asp:BoundField HeaderText="Title" DataField="Title" />
          <asp:ButtonField ButtonType="Link" CommandName="Select" Text="Details..." />
        </columns>
      </asp:GridView>

      <asp:SqlDataSource
        id="SqlDataSource1"
        runat="server"
        ConnectionString="<%$ ConnectionStrings:MyNorthwind %>"
        SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees">
      </asp:SqlDataSource>

      <hr />

      <asp:DetailsView
        id="DetailsView1"
        runat="server"
        DataSourceID="SqlDataSource2"
        AutoGenerateRows="False"
        AutoGenerateInsertButton="True">
        <fields>
          <asp:BoundField HeaderText="First Name" DataField="FirstName" ReadOnly="False"/>
          <asp:BoundField HeaderText="Last Name" DataField="LastName" ReadOnly="False"/>
          <asp:TemplateField HeaderText="Title">
            <ItemTemplate>
              <asp:DropDownList
                id="TitleDropDownList"
                runat="server"
                selectedvalue="<%# Bind('Title') %>" >
                <asp:ListItem Selected="True">Sales Representative</asp:ListItem>
                <asp:ListItem>Sales Manager</asp:ListItem>
                <asp:ListItem>Vice President, Sales</asp:ListItem>
              </asp:DropDownList>
            </ItemTemplate>
          </asp:TemplateField>
          <asp:BoundField HeaderText="Notes" DataField="Notes" ReadOnly="False"/>
        </fields>
      </asp:DetailsView>


      <asp:SqlDataSource
        id="SqlDataSource2"
        runat="server"
        ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
        SelectCommand="SELECT * FROM Employees"
        InsertCommandType = "StoredProcedure"
        InsertCommand="sp_insertemployee"        
        OnInserting="On_Inserting"
        OnInserted ="On_Inserted"
        FilterExpression="EmployeeID={0}">
        <FilterParameters>
          <asp:ControlParameter Name="EmployeeID" ControlId="GridView1" PropertyName="SelectedValue" />
        </FilterParameters>
      </asp:SqlDataSource>

<!-- 
     -- An example sp_insertemployee stored procedure that returns
     -- the primary key of the row that was inserted in an OUT parameter.
     CREATE PROCEDURE sp_insertemployee 
        @FirstName nvarchar(10), 
        @LastName nvarchar(20) , 
        @Title nvarchar(30), 
        @Notes nvarchar(200), 
        @PK_New int OUTPUT
      AS
        INSERT INTO Employees(FirstName,LastName,Title,Notes)VALUES (@FirstName,@LastName,@Title,@Notes)
        SELECT @PK_New = @@IDENTITY
        RETURN (1)    
      GO
-->      

      <asp:Label 
        id="Label1"
        runat="server" />
      
    </form>
  </body>
</html>

En el ejemplo de código siguiente se muestra cómo controlar el RowUpdating evento generado por el GridView control para cancelar posiblemente una acción de base de datos realizada por un SqlDataSource control asociado al GridView control .

<%@Page  Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

 // Set helper text and cancel the update if the values submitted to update the row
 // do not meet requirements.
 private void OnRowUpdatingHandler(Object source, GridViewUpdateEventArgs e) {
    // You can examine the values submitted by the user and perform additional
    // processing as required.
    if (e.OldValues[0].Equals("Nancy")) {
        e.Cancel = true;
        Label1.Text="This Row is Not Updatable!";
    }
 }

 // Ensure any helper text is cleared.
 private void OnRowCancellingHandler(Object source, GridViewCancelEditEventArgs e) {
    Label1.Text="";
 }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <asp:SqlDataSource
          id="SqlDataSource1"
          runat="server"
          DataSourceMode="DataSet"
          ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
          SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees"
          UpdateCommand="Update Employees SET FirstName=@FirstName,LastName=@LastName,Title=@Title WHERE EmployeeID=@EmployeeID">
      </asp:SqlDataSource>

      <asp:GridView
          id="GridView1"
          runat="server"
          AutoGenerateColumns="False"
          DataKeyNames="EmployeeID"
          AutoGenerateEditButton="True"
          DataSourceID="SqlDataSource1"
          OnRowUpdating="OnRowUpdatingHandler"
          OnRowCancelingEdit="OnRowCancellingHandler">
          <columns>
              <asp:BoundField HeaderText="First Name" DataField="FirstName" />
              <asp:BoundField HeaderText="Last Name" DataField="LastName" />
              <asp:BoundField HeaderText="Title" DataField="Title" />
          </columns>
      </asp:GridView>

      <asp:Label
          id="Label1"
          runat="server">
      </asp:Label>

    </form>
  </body>
</html>

<%@Page  Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

 ' Set helper text and cancel the update if the values submitted to update the row
 ' do not meet requirements.
 Sub OnRowUpdatingHandler(ByVal source As Object, ByVal e As GridViewUpdateEventArgs)
    If e.OldValues(0).Equals("Nancy") Then
        e.Cancel = "True"
        Label1.Text="This Row is Not Updatable!"
    End If
 End Sub 'OnRowUpdatingHandler

 ' Ensure any helper text is cleared.
 Sub OnRowCancellingHandler(ByVal source As Object, ByVal e As GridViewCancelEditEventArgs)
    Label1.Text=""
 End Sub 'OnRowCancellingHandler
</script>


<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <asp:SqlDataSource
          id="SqlDataSource1"
          runat="server"
          DataSourceMode="DataSet"
          ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
          SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees"
          UpdateCommand="Update Employees SET FirstName=@FirstName,LastName=@LastName,Title=@Title WHERE EmployeeID=@EmployeeID">
      </asp:SqlDataSource>

      <asp:GridView
          id="GridView1"
          runat="server"
          AutoGenerateColumns="False"
          DataKeyNames="EmployeeID"
          AutoGenerateEditButton="True"
          DataSourceID="SqlDataSource1"
          OnRowUpdating="OnRowUpdatingHandler"
          OnRowCancelingEdit="OnRowCancellingHandler">
          <columns>
              <asp:BoundField HeaderText="First Name" DataField="FirstName" />
              <asp:BoundField HeaderText="Last Name" DataField="LastName" />
              <asp:BoundField HeaderText="Title" DataField="Title" />
          </columns>
      </asp:GridView>

      <asp:Label
          id="Label1"
          runat="server">
      </asp:Label>

    </form>
  </body>
</html>

Comentarios

Cuando se crea un delegado SqlDataSourceCommandEventHandler, se identifica el método que controlará el evento. Para asociar el evento al controlador, se debe agregar una instancia del delegado al evento. Siempre que se produce el evento, se llama a su controlador, a menos que se quite el delegado. Para obtener más información acerca de cómo controlar eventos, vea controlar y provocar eventos.

Métodos de extensión

GetMethodInfo(Delegate)

Obtiene un objeto que representa el método representado por el delegado especificado.

Se aplica a

Consulte también